In order to provide ease of masonry construction work at site and to reduce the period of time required for the construction work, a masonry wall structure composed of hollow concrete blocks is in wide use typically as a retaining wall which is a wall for sustaining the pressure of earth behind the wall structure. Among such hollow concrete blocks is known a built-up type reinforced-concrete block unit which is composed of initially separate component panels. The reinforced-concrete component panels for such a built-up masonry block unit are prefabricated as separate members and are combined together into hollow block form at the site of construction.
The reinforced-concrete block units used to build a masonry wall structure such as typically a retaining wall structure are largely broken down to ordinary rectangular or parallelopiped block units laid in a number of courses and corner block units each to form the corner edge of each of the courses. While various types of hollow built-up concrete block units have thus far been proposed and put to practical use, only scarce research and development efforts have been paid to improve corner block units of the hollow built-up type.
An ordinary corner block unit for use in a retaining wall structure has a fixed corner angle and a vertical edge inclined at a fixed angle. The angle of inclination of the vertical edge of such a known corner block unit is usually selected to be proper to the angle of inclination of the corner edge of a retaining wall structure having a standard battered corner edge. The corner angle of retaining walls being different from one retaining wall structure to another, however, corner block units having fixed corner angles are relatively costly and inconvenient for use. This is primarily because of the fact that corner block units with various angle corners must be kept in stock, laid in a stock or designed and prefabricated to exactly suit the corner angles of the retaining wall structures to be constructed.
It is, accordingly, an important object of the present invention to provide an improved corner block unit having an adjustable corner angle in addition to a vertical edge inclined at a fixed angle.
In order that a corner block unit have an adjustable corner angle, the corner block unit is composed of a pair of block members which are angularly spaced apart at a desired angle about a vertical axis located at the bottom of the vertical edge of the block unit. The two block members are preferably interlocked together by suitable rigid joint members including at least one joint member secured to one of the block members and at least one joint member secured to the other block member. These at least two joint members are rigidly held together by suitable fastening means such as preferably bolts and nuts passed through openings respectively provided in the joint members.
It is, thus, another important object of the present invention to provide an improved corner block unit composed of a pair of block members which can be angularly spaced apart at a desired angle and which are interlocked together by at least one joint member secured to one of the block members and at least one joint member secured to the other block member.
It is still another important object of the present invention to provide an improved corner block unit composed of a pair of block members which are interlocked together by at least two joint members which are rigidly held together by bolts and nuts.
In order that the joint members respectively secured to the two block members be thus fastened together by means of bolts and nuts, the joint members must be bent, curved or otherwise deformed to provide a desired angle between the block members. Thus, the corner block units to be used for the construction of a retaining wall structure are, before or after they are hauled to the site of construction, set to provide a desired corner angle with the joint members of each of the corner block units bent or curved and thereafter bolted together either manually or with use of any simple, manually operated working implements. Professional skills may be required to have the joint members bent or curved to provide correct corner angles for all the corner block units to be put to use. Highly skilled techniques may also be indispensable for having the joint members bolted together while maintaining the two block members of each corner block unit in correct positions with respect to each other. If the block members of some of the corner block units have failed to be paired correctly, not only poor external appearance but insufficient structural strength of the retaining wall structure would result. The necessity for the meticulous care and possibly the large amounts of time and labor required for the bending and bolting of the joint members is objectionable from the view point of working efficiency at the site of construction or factory and for the economy of construction.
It is, therefore, still another important object of the present invention to provide an improved corner block unit composed of a pair of block members which are interlocked together by at least two joint members which can be easily and correctly held together by means of bolts and nuts without having recourse to professional skills.